The number of images to be acquired in one checkup has been enormously increased and loads on diagnosticians and radiologists have been more and more increased with development of medical image diagnostic devices. Since it becomes possible to acquire a large number of images, in particular, in an X-ray CT (Computed Tomography) device, an immense amount of labor has become necessary for a doctor in tumor diagnosis. Since an increase in labor taken for such diagnosis may induce an oversight and an erroneous diagnosis, it is demanded to reduce it as much as possible. Therefore, a technology (CAD: Computer Aided Detection) that automatically extracts a region concerned such as a tumor and so forth and a device with that technology loaded are proposed.
In Non-Patent Literature 1, for the purpose of extracting a liver tumor, a technique of applying a Region Growing method of extracting a point which is the highest in X-ray absorption coefficient (hereinafter, a luminance value) by using an image to which a liner pattern extraction filter has been applied and setting the extracted point as a seed to an original image is proposed.
In Non-Patent Literatures 2 and 3, techniques of generating a histogram distribution of the X-ray absorption coefficient (hereinafter, the luminance value) from the original image, obtaining a parameter of each distribution by assuming a luminance value distribution of a region concerned to be a Gaussian distribution and extracting the region concerned on the basis of the obtained luminance value distribution are proposed.
In Patent Literature 1, a technology of selecting an image processing procedure and parameters thereof which have been set in advance from image data and image incidental information and executing it.